1. Field of the invention
The invention relates to a digital switching network for switching digital signals of different rates contained in a multiplexed channel, which is divided into frames, words with a fixed number of bits per time slot being switched through every time, which switching network comprises for each of the multiplexed channels an input stage and an output step and a common switch step for each of the channels to be switched through. The use of such switching networks can particularly takes place in the case when multiplexed signals which originally have different rates are supplied by one or more subscribers, and are intended for several other subscribers. In this connection it is convenient to consider the case of subscribers who transmit signals for telephone traffic and data communication in one 64 kbit/s channel.
2. State of the art
A switching network of the sort described is known from reference D1. A drawback of this proposal is that signals with a low rate are collected till an eight-bit word is full, so that inadmissible delays can occur.
A proposal known from reference D2 describes a switching network which switches through bit by bit, due to which, it is true, a quick switching through is effected, but, on the other hand, the limit of the switching capacity of the network is already reached with a relatively small number of channels.
A proposal to have each signal switched at a certain rate by a separate switching network is known from reference D3. In practice this procedure, however, leads to a rather extensive switching system with relatively much idle time.